Paper interleaver device

ABSTRACT

A device for interleaving individual thin, flexible sheets of paper or similar material with a series of relatively thick flat articles (e.g., hamburger patties) as those articles fall along a defined stacking path terminating at a stacking position, comprising a carriage with grippers for pulling each flexible sheet from a support and across a shaping member that bends the sheet sufficiently so that the sheet becomes self-supporting as a cantilever member. The carriage takes the sheet to an interleaving position on the stacking path, where one of the articles engages the sheet and carries it to the stacking position. The grippers release the cantilever sheet at about the time the sheet is engaged by the moving article; the carriage then returns for the next sheet. The sheet supply may comprise a hopper with stacked pre-cut sheets, or may constitute a synchronized knife for cutting a sheet from a continuous web just prior to its engagement by the grippers.

United States Patent Leltan 1 July 11, 1972 [54] PAPER INTERLEAVER DEVICE 0' CondO" Assistant Examiner-Neil Abrams [72] inventor: Henry N. bekan, Chicago, Ill. i Dom & i n

[73] Asslgnee: Fol-max, Inc., Moltena, ill. I ABSTRACT [22] 1970 A device for interleaving individual thin. flexible sheets of [21] Appl. No.: 90,563 paper or similar material with a series of relatively thick flat articles (e.g.. hamburger patties) as those articles fall along a defined stacking path terminating at a stacking position. com- [52] US. Cl. ..$3/l57, l7/322, prising a carriage with grippem for pumng each flexible shce f d th s l 1 Int. Cl. ..B65h 25/08, B65b 35/50. B656 4 l I06 fgfij fifig 'ggg g, fl;fifi j 122, a candever membet- The i g takes the sheet 0 an inter; 271/ 44 A leaving position on the stacking path, where one of the articles engages the sheet and carries it to the stacking position. The [56] Ram CM grippers release the cantilever sheet at about the time the HTS sheet is engaged by the moving article; the carriage then UNITED STATES PATE returns for the next sheet. The sheet supply may comprise a 3,l26,683 3/1964 Richards et a] ..53/l22 hopper with stacked pre-cut sheets, or may constitute a 3,388,529 6/1968 Holly ..$3/ I22 synchronized knife for cutting a sheet from a continuous web just prior to its engagement by the grippers.

l7 Chins, ll Drawing figures PATENTEDJUL 1 1 I972 SHEET 10F 6 INVENTOR HENRY N. LE KAN ATTORNEYS PITEN'TEDJIILH m2 3.675.387

SHEET ZUF 6 INVENTOR HENRY N LEKAN lev ATTORNEYS INVENTOR HENRY N LEKAN ATTORNEYS PLATENTEBJIJL I 1 m2 SHEET l 0F 6 INVENTOF? HENRY N LEKAN ATTORNEYS PKTENTEDJHL 1 1 1972 SHEET 5 OF 6 wwm mmm

INVENTOR HENRY N LEKAN 2 AT TO R NEYS P'ATEN'TEDJuLII I972 3.675.387

sum 5 or 6 FIGJO INVENTOR HENRY N. LEKAN PAPER IN'I'ERLEAVER nsvrcs BACKGROUND OF THE INVENTION In many manufacturing applications, and particularly in food processing machinery, it is highly desirable to separate finished articles in a package by interleaving the articles with thin, flexible sheets of waxed paper, cellophane, plastic film, or other very thin, flexible material. For example, in packaging a plurality of meat slices or hamburger patties, individual sheets of waxed paper or like material inserted between adjacent pieces of meat prevent the meat from sticking together and preserve the integrity of the individual meat pieces. This is particularly desirable where the meat is to be frozen or is subjected to other conditions that may tend to cause the individual meat pieces to cling to each other.

The same situation is presented with sliced cheese; where the interface between individual slices tend to be lost and the cheese slices tend to grow" back together. Olten, in the basic manufacturing or processing equipment, there is some stage of operation at which the individual hamburger patties or other such articles traverse a given stacking path terminating at a stacking position; the preferred technique is to suspend individual sheets of waxed paper or the like at some intermediate position on the path so that each article, moving along the path, picks up a sheet of paper and comes to rest in a stack in which the articles are interleaved one-for-one with the paper sheets.

One known interleaving device, comprising an accessory to a hamburger patty machine and utilized for interleaving paper sheets with hamburger patties, is described in Richards et al. U.S. Pat. No. 3,126,683, issued Mar. 3 l I964. In the Richards device, the hamburger patties fall freely through space along a predetermined path terminating at a stacking destination. In that device, a sheet of paper is supported at its opposite edges on a frame positioned so that the paper sheet extends across the path of movement of the hamburger patties. A falling hamburger patty engages the sheet of paper and carries the paper with it, through the frame, and onto the stack. This device works quite efficiently, in many applications, but does require the use of paper that is wide enough and stiff enough to be self-supporting on frame members that are spaced by a distance greater than the maximum dimension of the harnburger patties. Consequently, the paper must be substantially wider than the patties with which it is interleaved, particularly if a thin and highly flexible paper is employed. The apparatus also has some tendency toward malfunction, when extremely thin and flexible sheets of paper are used, in that they may occasionally fall from the frame before being engaged by the falling hamburger patty, resulting in a failure to achieve effective interleaving.

Another prior art interleaving apparatus is set forth in Bush US. Pat. No. 2,877,120 issued Mar. 10, 1959, in which the individual sheets of paper are cut from a continuous web by a knife mechanism. The paper is held at the cutting position, projecting outwardly from the knife as a cantilever member, and is supported by a jet air stream that impinges upon the bottom of the paper. A slice of meat or similar article engages the cantilever-supported paper and carries the paper with it to a stacking location. The jet stream, however, is somewhat difficult to adjust to maintain support of the paper in the proper position to be interleaved with a passing object. Moreover, the mechanism is best employed with an apparatus in which the movement of the meat slices or other articles is more closely controlled than in many hamburger patty machines and the like, where there may be some limited variations in the movement of the objects along the stacking path.

In most interleaving devices using stacks of precut sheets of thin waxed paper or like material, the individual sheets are initially pulled from the stack in a direction including a substantial vector component parallel to the plane of the paper. This produces a substantial tendency toward double-sheeting, particularly if the coefficient of friction between sheets varies, as is often the case. Dou ble-sheeting is highly undesirable; in

some applications, it is completely unacceptable. The problem may be aleviated somewhat by using a tear pin with specially punched sheets, but this expedient introduces an almost equally objectionable problem of chaff, from the punched paper, engaging and adhering to the food product. A similar difficulty is experienced with many interleavers that stack up two or more sheets at the interleaving position whenever the hamburger patty machine or other food processing equipment with which the interleaver is utilized malfunctions and fails to pass patties through the interleaving position for one or more cycles'of operation.

SUMMARY OF THE INVENTION It is a principal object of the present invention, therefore, to provide a new and improved sheet interleaver device for interleaving individual thin, flexible sheets of paper, cellophane, plastic film, or like material with a series of relatively thick, flat articles such as hamburger patties, as the articles traverse a given stacking path, that is highly reliable in operation and adaptable to use with a wide variety of different forms of processing equipment.

A particular object of the invention is to provide a new and improved sheet interleaver device that permits movement of an extremely flexible sheet of paper or the like from a supply location to an interleaving location, when supported as a cantilever element, without requiring the use of an air stream or other supplemental means for supporting the free end of the sheet.

Another object of the invention is to provide a new and improved sheet interleaver device for interleaving hamburger patties or similar articles with thin, flexible sheets of paper or plastic film that supports the paper or film as a cantilever element and effectively releases the film in timed relation to its engagement by a falling article.

A further object of the invention is to provide a new and improved paper supply and shaping mechanism for a paper interleaver that automatically bends the paper to afford adequate strength for cantilever support as an incident to removal of the paper from a supply location.

An additional object of the invention is to provide a new and improved sheet interleaver device, suitable for use with high speed food processing machinery, that inherently and consistently feeds single sheets with no appreciable tendency toward double sheeting.

Another object of the invention is to provide a new and improved sheet interleaver device, adapted to use with ham burger patty forming machines and other like food-processing machines, that cannot stack multiple sheets in the interleaving position in the event of a malfunction of the food-processing machine.

A specific object of the invention is to provide a new and improved sheet interleaver device, having the aforementioned operating characteristics, that is simple and inexpensive in construction, reliable in operation, and requires a minimum of maintenance.

Accordingly, the invention pertains to a sheet interleaver device for interleaving individual, thin, flexible sheets of paper, cellophane, plastic film or like material with a series of relatively thick, flat articles as the articles traverse a given stacking path one-by-one in spaced relation to each other, the path terminating at a stacking position. The interleaver device comprises support means for supporting a thin flexible sheet of given length and width at a transfer position adjacent to but spaced from an intermediate interleaving position on the stacking path. Supply means are provided for positioning a series of thin, flexible sheets on the support means, together with trand'er means for transferring a single flexible sheet from the support means along a predetermined transfer path originating at the transfer position and terminating at the aforementioned interleaving position at the intersection of the transfer path and the stacking path. The transfer means supports the sheet cantilever-fashion at the interleaving position. Shaping means are interposed in the transfer path to bend each sheet to impart sufficient stiffness to the sheet to render it self-supporting as a cantilever member. The transfer means is operated in synchronism with the movement of the aforesaid articles along the stacking path so that each article engages a cantilever sheet at the interleaving position and carries that sheet with it to the stacking position.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a sheet interleaver device constructed in accordance with one embodiment of the present invention;

FIG. 2 is a detail plan view, partially in cross section, of the sheet supply hopper for the interleaver of FIG. 1;

FIG. 3 is a detail sectional view of the supply hopper taken approximately along line 3-3 in FIG. 2;

FIG. 4 is a detail sectional view, similar to FIG. 3, illustrating another position for the hopper;

FIG. 5 is a detail front elevation view, partly in cross section, of the supply hopper for the interleaver device of FIG. 1;

FIG. 6 is an elevation view of an interleaver device constructed in accordance with another embodiment of the invention;

FIG. 7 is a plan view, partly in cross section, of the interleaver device of FIG. 6;

FIG. 8 is a detail view illustrating the cantilever suspension of a thin flexible sheet in the apparatus of FIGS. 6 and 7;

FIG. 9 is a plan view, partly in cross section, of interleaver device constructed in accordance with a further embodiment of the invention;

FIG. 10 is an elevation view taken approximately along line l0l0 in FIG. 9; and

FIG. I] is a schematic illustration of a part of the controls for the interleaver device of FIGS. 9 and 10.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. I illustrates a sheet interleaver device 20 constructed in accordance with one embodiment of the present invention. The interleaver device 20 comprises a horizontal base plate 21 that is aligned with a stacking path 23 traversed by a series of relatively thick, flat articles 22, such as hamburger patties, cheese slices, or the like. The stacking path 22, which may be at the output end of a hamburger patty machine, is a free-fall path originating above the interleaver 20 and terminating at a stacking location 24. As each of the articles 23 traverses stacking path 22, it passes through an intermediate interleaving position 25 constituting the intersection of stacking path 22 with a transfer path 26, as described more fully hereinafter.

At the right-hand end of base plate 21, as seen in FIG. I, a pair of vertical frame members 27 and 28 are mounted on the base plate. A main drive shaft 29 extends across interleaver 20 and is journalled in appropriate bearings in the two frame members 27 and 28. The right-hand end of shaft 29, as seen in FIG. I, carries a gripper control cam 31. The lefi-hand end of drive shaft 29 has a sprocket 32 mounted thereon; sprocket 32 is engaged by a drive chain 33 that extends around another sprocket 34. Sprocket 34 is mounted at one end of an actuating shaft 35 that also extends between and is journalled in appropriate bearings in the frame members 27 and 28.

Two hopper actuating cams 36 and 37 are mounted on the central portion of the actuating shaft 35, as shown in FIG. 2. As seen in FIG. I, shaft 35 extends outwardly of frame member 27, a crank 38 is mounted on the outboard end of the shaft. A link 39 has one end pivotally connected to the free end of crank 38. The other end of link 39 is pivotally connected to a gear segment 4]. Gear segment 41 is rotatably mounted on a short cantilever shaft 42 supported upon frame member 27. The gear segment is disposed in meshing engagement with a gear 43 that is mounted upon another short shaft 44 that projects outwardly of frame member 27. A drive gear 45 is also mounted on the shaft 44, and is connected to gear 43 so that the two gears rotate conjointly. Gear 45 engages an elongated rack 46 that is a part of transfer mechanism generally indicated by reference numeral 47.

Transfer mechanism 47 includes a pair of elongated cantilever guide and support members 48 and 49 that are mounted upon the frame members 28 and 27, respectively, and that project from the frame members parallel to the transfer path 26. A carriage 5I is mounted upon guide members 48 and 49 and is slidably movable along the guide members. Carriage 51 includes a pair of elongated arms 52 and 53 extending parallel to but are substantially spaced from transfer path 26. Carriage arm 52 terminates, at its free end, in an inward projection that supports a vacuum gripper pad 54. Similarly, the free end of carriage arm 53 comprises an inwardly directed projection that supports a second vacuum gripper pad 55. Carriage 51 is provided with internal passageways affording a manifold that connects the vacuum grippers 54 and 55 with a port 56 that is in turn connected to a flexible vacuum hose 57. Vacuum hose 57 is connected to a control valve 58 having a cam follower plunger 59 that engages cam 3I. Control valve 58 is provided with an inlet connection 61 that is connected to a vacuum pump (not shown).

Interleaver 20 further comprises a paper supply means including a storage hopper 62 having a front wall 63, side walls 64 and 65, and two shortened partial rear walls 66 and 67. The bottom 68 of the paper supply hopper 62 affords a support for a stack of pre-cut individual sheets of thin flexible wax paper, cellophane, plastic film or the like as generally indicated by reference numeral 69. The support for stack 69 is supplemented by two small corner supports 71 and 72 located in the front corners of hopper 62, as best shown in FIG. 2. There is an opening 73 across the bottom portion of the front hopper wall 63. In addition, there are two openings 74 and 75 in the lower front portions of the hopper side walls 64 and 65 respectively, as shown in FIGS. I, 3 and 4.

At the rear of hopper 62, a pair of support plates 81 and 82 are mounted upon the lower portions of the hopper side walls 65 and 64, respectively (FIGS. I and 2). The support plates are rigidly affixed to the hopper walls, as exemplified by the welded connection indicated in FIG. I. The front portion of hopper support plate 81 forms a socket for receiving a support shaft 83 that is affixed to a projection 85 extending forwardly from frame member 27 (FIG. I). Similarly, the forward portion of hopper support plate 82 affords a socket for receiving a support shalt 84 (FIG. 2) that is mounted on frame member 28. It is thus seen that hopper 62 is pivotally mounted upon the two shafts 83 and 84.

The rearwardly extending portion of hopper support plate 81 projects beneath the cam 37, and comprises a cam follower 87. Similarly, the rearwardly extending portion 86 of hopper support plate 82 comprises a cam follower that engages cam 36. The cam and cam follower combinations 36, 86 and 37,87 afford a means for controlled pivotal movement of hopper 62 as described more fully hereinafter.

A shaper plate 88 is mounted in the bottom of hopper 62, being secured to the hopper bottom by appropriate means such as a pair of screws 90. Shaper plate 88 projects forwardly of the hopper bottom 68 and across a large front opening in the bottom of the hopper. The forward tip 89 of shaper plate 88, which is spaced a short distance from the front wall 63 of the hopper, is of V-shaped configuration with the tip of the V rounded to prevent tearing of the paper during a transfer operation as described hereinafter. The stack of paper sheets 69 rests upon shaper plate 88, hopper bottom 68, and hopper comers 71 and 72, all of these elements forming a part of the support means for supporting the thin flexible sheets of paper at the transfer position from which those sheets are moved to the interleaving position 25 (FIG. I). The lowermost paper sheet 92 rests directly on these elemenm.

In considering operation of interleaver device 20, it may first be assumed that the device is in the operating condition illustrated in FIG. I with carriage 5] advanced to the extreme leftward limit of its travel along guides 48 and 49, supporting a single sheet of paper 93 at the interleaving position 25. Cam

31 has just reached a rotational position at which it depresses cam follower 59, actuating control valve 58 to cut off the connection from hose 57 to a vacuum pump that is connected to the valve port 61. Consequently, the vacuum pads 54 and 55 are cut off from the vacuum pump and release the paper sheet 93. A hamburger patty or other article 23 is already falling along the stacking path 22 and is about to impinge upon sheet 93. The continued downward movement of article 23 causes that article to contact sheet 93 and to carry the sheet downwardly with the article to the stacking location 24, coming to rest on top of the article and the paper sheet that are already at the stacking position.

Drive shaft 29 is rotated continuously in synchronism with the hamburger patty machine or other processing equipment with which interleaver is utilized. A chain drive or other ap propriate drive (not shown) can be connected from the processing machine to drive shaft 29 to assure effective synchronized operation. As shaft 29 continues to rotate in the indicated clockwise direction (FIG. 1), actuating shaft 35 is rotated in the same direction by means of the drive connection afforded by sprockets 32 and 34 and chain 33. The resulting clockwise rotation of actuating shaft 35 rotates crank 38; the connection afforded by link 39 drives gear segment 4! in a clockwise direction from the position illustrated in FIG. 1. As a consequence, gear 43 is rotated counterclockwise, imparting a similar rotation to gear 45 and initiating a return movement of rack 46 in the direction indicated by the arrow A.

At first, as rack 46 begins its return movement (arrow A) there is no corresponding movement of carriage 51, since there is a substantial lost motion in the connection between rack 46 and carriage 51. After rack 46 has moved through a short distance, however, a stop 96 mounted on the rack engages a shoulder 97 on carriage 5 l and begins to move the carriage to the right toward the supply means comprising hopper 62. This movement of carriage 51 is continued until the vacuum gripper pads 54 and 55 are at the transfer position shown in FIG. 2, aligned with the bottom of the paper stack 69 at the front forward corners of the bottom opening 95 in the hopper. During the interval in which the return movement of carriage SI is carried out, cam 31 maintains the control valve plunger 59 depressed, so that there is no premature functioning of the vacuum gripper pages as the grippers move into transfer position below the bottommost sheet 92 in the stack 69.

During the return movement of carriage 51, hopper 62 is maintained in its normal elevated position, shown in FIGS. 1 and 4. When the carriage reaches the transfer position immediately below the hopper, however, as shown in FIG. 2, the reduced diameter portions of the cams 36 and 37 come into alignment with the cam followers 86 and 87 on the hopper support plates 82 and 81 respectively. Consequently, hopper 62 pivots downwardly from its normal elevated position (FIG. 4) to the position shown in FIG. 3, at which the vacuum gripper pads 54 and 55 come into contact with the lowermost sheet 92 on the support means comprising hopper bottom 68, shaper plate 88, and hopper bottom corners 7] and 72. While the hopper is in the depressed position illustrated in FIG. 3, the continued rotation of cam 31 (FIG. 1) brings the reduceddiameter portion of that cam into alignment with valve control plunger 59. Plunger 59 is released, actuating control valve 58 to an operating condition in which it completes a connection from the vacuum pump to hose 57 and hence to the manifold in carriage 51 that is connected to the vacuum gripper pads 54 and 55. The evacuation of the vacuum system to which pads 54 and 55 are connected causes the pads to grip the front corners of the bottom paper sheet 92. This is the operating condition illustrated in FIG. 3.

Continuing rotation of shafts 29 and 35, and particularly shaft 35, rotates cams 36 and 37 to again bring the full-diameter portions of these cams into engagement with cam followers 86 and 87, as a consequence, supply hopper 62 is pivoted clockwise back from the position of FIG. 3 up to that shown in FIG. 4. The lowermost paper sheet 92 is still gripped by the vacuum pad grippers 54 and 55, however, so that this sheet is pulled downwardly through the bottom opening 95 in the hopper and over the edges of shaper plate 88 as shown in FIGS. 4 and 5. As this happens, the side edges of the paper sheet are pulled slightly inwardly and the sheet is bent at a definite angle as clearly illustrated in FIG. 5.

The continuing rotation of shaft 35, which initially drove rack 46 and carriage 5] to the right in the direction of arrow A, is reversed as crank 38 passes its point of central alignment with link 39. As a consequence, the clockwise rotation of gear segment 41 is reversed and the gear segment begins to rotate in a counterclockwise direction. At first, this does not move carriage 51; the lost motion must be taken up by sulficient movement of rack 46 to bring its stop member 98 into engagement with a second shoulder 99 on carriage 5|. This allows sufficient time to permit the initial gripping of the lowermost sheet 92 and the pulling of that sheet downwardly from hopper 62 to the position shown in FIGS. 4 and 5.

The continuing counterclockwise rotation of gear segment 41, acting through gears 44 and 45, now drives carriage 51 back to the lefl as indicated by arrow B (FIG. I). As the carriage moves away from supply hopper 62, it continues to pull the lowermost sheet of paper 92 across the V-shaped shaping member 88, effectively bending or creasing the paper sheet throughout its length. Thus, as the paper sheet emerges, gripped by the vaduum pad grippers 54 and 55, it is bent or creased with a longitudinal crease 94 as illustrated by sheet 93 in FIG. 1. The bend in the thin flexible paper sheet is critically important to operation of interleaver 20; without it, the thin, flexible sheet would not be self-supporting as a cantilever member. With the sheet shaped to form the requisite bend 94, the sheet is self-supporting as a cantilever member and ends up at interleaving position 25 supported cantilever-fashion by only the two corner grippers 54 and 55. That is, transfer means 47 effectively transfers the flexible sheet from the support means in supply hopper 62, moving the sheet along transfer path 26 to its termination at interleaving position 25, and supports the sheet cantilever-fashion at the interleaving position for a short period of time.

lnterleaver 20 is synchronized one-for-one with the cyclic operation of the hamburger patty machine or other processing apparatus that releases articles 23 to fall along stacking path 22. When interleaver 20 again reaches the position illustrated in FIG. 1, with the sheet centered at interleaving position 25, another article 23 is released to fall along path 22. Cam 31 cuts off the vacuum grippers 54 and 55 shortly before the paper sheet is engaged by the falling article, so that the falling article carries the sheet downwardly to stacking position 24.

interleaver 20 is highly reliable in its operation and is adaptable to use with a wide variety of different forms of processing equipment. The interleaver is not limited to use with apparatus in which articles 23 move along a vertical path, although this is its simplest application. It can be used with articles traversing a horizontal or other path, provided appropriate means are afforded for continuously advancing new sheets to the feed position on the support means at the base of supply hopper 62.

Interleaver 20 is self-timing and requires only a single drive connection that operates in synchronism with the processing machine that releases articles 23 for movement along stacking path 22. The interleaver does not require an air stream or any other supplemental means for supporting the paper sheet, such as the sheet 93, at interleaving position 25. Instead, the sheet is automatically bent, by the simple shaping member 88, so that the sheet becomes self-supporting even though suspended as a cantilever member. The vacuum grippers of interleaver 20 are of substantial advantage, permitting accurately controlled release of each paper sheet, with appropriate timing, so that the article moving along the stacking path always engages the paper sheet just afier release, preventing any sliding or other misalignment of the sheet relative to the article. Moreover, the vacuum grippers prevent any stacking of multiple sheets at the interleaving position, and the vertical withdrawal of sheets from the stack avoids double-sheeting. Nevertheless, interleaver 20 is quite simple and inexpensive in construction and requires a minimum of maintenance.

FIGS. 6 and 7 illustrate a sheet interleaver device 120 constructed in accordance with another embodiment of the invention. interleaver 120 is shown as an attachment to a hamburger patty manufacturing machine 100, only the output portion of the hamburger patty machine being illustrated. The hamburger patty machine includes a mold plate 101 that moves reciprocally, as by the arrows D, into and out of alignment with a discharge cup 102 mounted upon a vertically movable support arm 103. In each cycle of operation of the hamburger patty machine 100, mold plate 101 starts from a retracted position as shown in FIG. 6, in which a mold cavity 104 in the mold plate is filled with ground meat. The mold plate advances to the extended position illustrated in FIG. 7, in which the mold cavity 104 is aligned with cup 102. Cup 102 then moves downwardly (arrow C, FIG. 6) and drives a molded hamburger patty 123 out of the cavity in the mold plate.

The hamburger patty 123 falls downwardly along a stacking path 122 to the stacking location 124. After the hamburger patty has been discharged from the mold plate, cup 102 is returned to the elevated position shown in FIG. 6 and mold plate 101 is retracted to its original position to be refilled with ground meat. This general type of meat processing equipment is well known in the art; accordingly, there is no necessity for illustrating or describing the meat pump and other operating components of the hamburger processing machine 100.

The interleaver device 120 of FIGS. 6 and 7 comprises a base plate 121 that is aligned with the stacking position 124 and defines the bottom of the stacking position. At the righthand end of interleaver 120, as seen in FIGS. 6 and 7, there are a pair of frame members 127 and 128 mounted on base plate 121. A cam shalt 135 extends across the interleaver and is journalled in suitable bearings in frame members 127 and 128. A pair of cams 136 and 137 are afiixed to shaft 135 for rotation therewith. Shaft 135 is driven by a chain 105 that engages a s rocket 106 mounted on the shaft. The other end of chain 105 engages a sprocket 107 mounted upon a shaft 108 that extends across the frame of the hamburger patty machine 100 and is journalled in suitable bearings mounted in the side frame members 109 and 110 of the hamburger patty machine.

Shaft 108 carries an additional sprocket 111 that is engaged by a chain 112 which also engages another sprocket 113 mounted upon a short shaft 114. A gripper control cam 131 is mounted upon shaft 114. At the other end of shaft 108, there is a roller 115 that rides upon and is rotated by an elongated rack member 146.

Rack member 146 is disposed in meshing engagement with a gear 145 mounted upon a short cantilever shaft 144 extending outwardly of the hamburger patty machine frame member 110. Shaft 144 also carries a gear 143 that is connected to gear 145 for rotation therewith. Gear 143 is in meshing engagement with a gear segment 141 mounted upon a shaft 142. Shaft 142 is a reciprocally operated shafl in the hamburger patty machine 100.

The right-hand end of rack 146 extends through a projection 150 on a carriage 151. Carriage 151 is a part ofa transfer means 147 for transferring individual sheets of paper or like thin, flexible material from a transfer position to an interleaving position 125 at the intersection of a transfer path 126 and the stacking path 122. Carriage 151 is mounted upon a pair of elongated guide members 148 and 149 that are affixed to and extend horizontally from the two interleaver frame members 128 and 127 respectively. Carriage 151 has two short arms 152 and 153 upon which are mounted two vacuum gripper cups 154 and 155 respectively. The carriage is provided with internal passageways comprising a vacuum manifold that is connected to a vacuum port 156 in turn connected to a flexible hose 157. Hose 157 is connected to a vacuum gripper control valve 158 operated by a plunger 159 that is engaged by the gripper control cam 131. A hose 161 is connected from control valve 158 to a vacuum pump (not shown).

interleaver device includes a supply hopper 162 positioned between frame members 127 and 128 at the right-hand side of the machine as illustrated in FIGS. 6 and 7. Supply hopper 162 comprises a front wall 163, side walls 164 and 165, and two short rear wall segments 166 and 167. A plate 168 is mounted in the bottom of the hopper, between side walls 164 and 165. A shaper plate 188 is mounted upon bottom plate 168 by two screws 190 and extends across the opten bottom of the hopper, toward front wall 163, terminating with a generally V-shaped tip 189 that is rounded to prevent tearing of the paper as the paper is withdrawn from the hopper, as described more fully hereinafter. A pair of small corner support members 171 and 172 are located at the front comers of the hopper. A stack 169 of thin, flexible paper sheets or other similar sheets is disposed in hopper 162, supported by the comer members 171 and 172, by the shaper plate 188, and by two bottom extensions 184 and 185 of side walls 164 and 165 respectively.

The right-hand end of the bottom plate 168 of hopper 162 is affixed to a bar 176, the ends of bar 176 being journalled in suitable bearings in the two frame members 127 and 128. Thus, bar 176 affords a pivotal mounting for hopper 162. The bottom of plate 168 is provided with a pair of cam follower projections that engage the two cams 136 and 137, as exemplified by the cam follower 187 in contact with cam 137 (FIG. 6).

in operation of interleaver device 120, a stack 169 of precut thin, flexible sheets of paper, cllophane, plastic film or like material is stored in hopper 162. The lowermost sheet in the supply 169 rests upon the support means comprising shaper plate 188, corner supports 171 and 172, and side plate extensions 184 and 185. At the beginning of a cycle, it may be assumed that the apparatus is in the position illustrated in F IG. 6, with the hamburger patty machine mold plate 101 filled with ground meat and ready to move from the retracted position of FIG. 6 to the advanced position of FIG. 7. Carriage 51 is at the right-hand end of its travel, with the vacuum gripper pads 154 and 155 located immediately below the front corners of hopper 162, as indicated by the position of gripper pad 155 in F 1G. 6.

From the position illustrated in FIG. 6, shaft rotates counterclockwise, bringing the two cam followers on the bottom plate 168 into alignment with the reduced diameter portions of cams 136 and 137. When this occurs, the weight of hopper 162 causes the hopper to pivot through a short distance, counterclockwise, lowering the front end of the hopper until the two vacuum pads engage the bottommost sheet in stack 169. Continued rotation of shaft 135 subsequently brings the full-diameter portions of earns 1.36 and 137 again into alignment with the cam followers (e.g., cam follower 187 on bottom plate 168 and pivots hopper 162 clockwise back to its original position as illustrated in FIG. 6.

The clockwise return movement of hopper 162 leaves the bottommost sheet gripped by the two vacuum gripper pads, so that this sheet is pulled downwardly through the bottom of the hopper and is creased by its engagement with the V-shaped tip 189 on shaper plate 188 (HO. 7). Consequently, the sheet is bent or creased in the same manner as described above for the previous embodiment of the invention and ends up in the configuration illustrated in FIG. 8. That is, the sheet 193, as it is pulled from the supply hopper, has a longitudinal crease or bend 194 such that the sheet is self-supporting as a cantilever member on the two vacuum gripper pads 154 and 155.

At about the time that hopper 162 is pivoted back to its original position, rack 146 begins to move to the left as indicated by arrow B. initially, there is no corresponding movement of carriage 151. After a short movement of rack 146, however, a stop member 198 on the rack engages a shoulder 199 on the extension portion of carriage 151. Thereafter, the continued movement of rack 146 in the direction of arrow B causes a corresponding movement of carriage 151. The carriage moves along guide members 148 and 149, along transfer path 126, until the carriage is positioned as shown in FIG. 7 with the paper sheet 193 supported cantilevenfashion at the interleaving position 125.

During the time interval in which carriage 151 moves from the transfer position of FIG. 6 to the interleaving position of FIG. 7, mold plate 101 advances to its extended position. At about the time that carriage 151 reaches the interleaving location 125, cup 102 moves downwardly in the direction of arrow C and drives a hamburger patty 123 out of the mold cavity in mold plate 101. The hamburger patty falls along stacking path 122 and engages the paper sheet 193 at the interleaving position 125, carrying the paper sheet downwardly to the stacking position 124 (FIG. 6).

The rotation of cam 131 is in synchronism with the movement of rack 146, since the drive for cam 131 is taken directly from the rack through roller 115, shaft 108, and the chain drive comprising chain 112. At the time the hamburger patty is driven out of the mold plate by cup 102, the full-diameter portion of cam 131 engages plunger 159 and actuates control valve 158 to cut off the connection from vacuum gripper pads 154 and 155 to the vacuum pump. Accordingly, the paper sheet that has been suspended at the interleaving position is released by the vacuum gripper pads so that it is free to fall with the hamburger patty. The entire operation is maintained in synchronism with the cyclic operation of the hamburger patty forming machine 100, since the interleaver drive is taken from the shaft 142 of the hamburger patty machine.

From the foregoing description, it can be seen that the basic operation of interleaver device 120 is essentially the same as that of the previously described interleaver 20, though there are some differences in mechanical construction. lnterleaver 120 is automatically maintained in synchronism with the barnburger patty machine to which it is connected. Each paper sheet, as it is withdrawn from supply hopper 162, is bent by shaper plate 188 to form a self-supporting cantilever element. Accordingly, the transfer means 147 is able to position each paper sheet at the interleaving position 125 without the necessity for any support element beneath the sheet and without any air blast or other support means for the sheet. Grippers 154 and 155 are easily actuated to release the sheet in appropriate timed relation to the discharge of each hamburger patty, assuring an efiective, accurately centered interleaving operation without distortions which could result if the sheets were still gripped at one edge when engaged by the hamburger patties. Each time a new sheet is withdrawn from the supply hopper 162, a new sheet is ready on the support afforded by the bottom elements in the hopper.

At the end of the cycle, when the hamburger patty has passed carriage 151, the direction of movement of rack 146 is reversed by reversal of the rotation of the reciprocating machine shaft 142. As the rack moves back in the direction of arrow A, a stop member 196 on the rack engages a shoulder 197 on the extension portion 150 of carriage 151. Accordingly, the return movement of rack 146 carries carriage 151 back to its original position, as shown in FIG. 6, ready to remove another sheet from supply hopper 162.

FIGS. 9, 10 and 11 illustrate an interleaver device 200 that is basically similar in its operation to the two previously described embodiments of the present invention but that includes a substantially different supply means for supplying individual thin, flexible sheets of paper or similar material to the interleaver. lnterleaver 200 includes a frame comprising two side plates 201 and 202 connected by a top plate 203 and a bottom plate 204. Side plate 202 includes a slot 206 for receiving a support shaft 208 (FIG. 10) and side plate 201 is provided with a similar slot for receiving a support shaft 207. Thus, the frame of the interleaver is pivotally mounted upon the two support shafts 207 and 208.

The right-hand end of side plate 201, as seen in FIGS. 9 and 10, includes an extension 209 with an upwardly projecting cam follower 211. A similar extension 210 of side plate 202 terminates in a cam follower lug 212 (FIG. 9). The two cam followers 211 and 212 engage two cams 213 and 214 respectively, the cams 213 and 214 being mounted upon a cam shaft 215.

At the left-hand side of the interleaver 200, as seen in FIGS. 9 and 10, there is a metal guide 216. The bottom 217 of the guide 216 constitutes a support plate for supporting a thin, flexible sheet of given length and width at a transfer position ready for transfer to an interleaving position as described more fully hereinafter. The support plate 217 is also a shaper plate, being provided with a V-shaped projection 218 with the tip of the V rounded to prevent tearing of the paper during operation of the interleaver. An upper guide 219 is located above the guide 216. The guide members are mounted upon the side plates 201 and 202 of the interleaver by appropriate means and may, for example, be tack welded or otherwise secured to the side plates.

The paper supply for interleaver 200 comprises a supply roll 221 from which a continuous web 222 of thin flexible paper is extended into the interleaver. The paper web 222 is guided into the right-hand end of the interleaver, as viewed in FIGS. 9 and 10, above the bottom plate 204 and below an internal guide 223 (FIG. 10). The paper web 222, during operation, is further extended out into the space between the bottom plate 217 of guide 216 and the upper guide 219 as described more fully hereinafter.

A knife blade 224 is mounted in interleaver 200 in alignment with the forward edge 225 of bottom plate 204; edge 225 is formed with a cutting surface to cooperate with the lower edge of knife blade 224. Blade 224 is suspended from an actuating mechanism 225, shown as a solenoid; the knife actuating mechanism may constitute a pneumatic or hydraulic cylinder or other operating device for driving blade 224 in a reciprocal vertical cutting motion. Two shafts 226 are affixed to blade 224 and extend upwardly above top plate 203, each of the shafts 226 having a return spring 227 mounted in encompassing relation thereto. Only one of the vertical shafts 226 and one spring 227 are shown in the drawings. The upper ends of the two shafts 226 are connected by a tie bar 228. The upper ends of the shafts 226 may be threaded to afford a convenient means for mounting the tie bar 228 and for adjusting its vertical position to thereby adjust the vertical range of movement of knife blade 224. Tie bar 228 is also connected to the armature shaft 229 of solenoid 225. The ends of knife blade 224 are engaged in guide slots in side plates 201 and 202, as illustrated by blade 224 and side plate 202 in FIG. 9, to assure controlled vertical movement of the knife blade.

An air cylinder 231 is mounted upon a bracket 232 on top plate 203, as shown in FIG. 10. The shaft 233 of cylinder 231 carries a stop member 235 and is connected to a rack 234. A rack guide and stop member 236 is mounted on side plate 201 in alignment with the lower end of rack 234. Rack 234 is disposed in meshing engagement with the input gear 237 of a unidirectional clutch 238. Gear 237 is mounted upon the outer shaft 239 of the clutch, constituting the input shaft. The output shaft 241 for clutch 238 is an internal shafi concentric with shaft 239. Output shaft 241 extends beyond the inner end of shaft 239, and carries a drive gear 242.

The drive gear 242 is positioned in meshing engagement with a driven gear 243 that is mounted on the end of the shaft for an upper paper feed roller 244 that extends across interleaver 200 between side plates 201 and 202. A lower paper feed roller 245 is aligned with roller 244. Preferably, the two paper feed rollers are provided with frictional surfaces to afford efficient and rapid paper feed from the supply roll 221.

lnterleaver 200 further includes a paper transfer means 247 comprising a carriage 251 which may be essentially similar in construction to the carriage 51 of interleaver 20 (FIGS. 1 and 2). Carriage 251 is mounted upon a pair of elongated guide members 248 and 249. The carriage includes two inwardly extending arms 252 and 253 which terminate in vacuum gripper cups 254 and 255. At the transfer position for carriage 251 (FIG. 9) the vacuum cups 254 and 255 are located immediately below the front end of the paper support means comprising the bottom plate 217 of paper guide 216, in the area that is left open in the bottom plate by the V-shaped configuration of the front end of the shaper plate.

A control switch 261 is positioned below the rear portion of the side plate extension 209, as best shown in H0. 10. Switch 261 is actuated between two different operating conditions by a plunger 262 that engages the side plate extension 209.

As shown in the schematic drawing of FIG. 11, control switch 261 has a fixed input terminal 262 that is electrically connected to a movable contact 263 engageable with either one of two output terminals 264 and 265. Input terminal 262 is connected to one side of a power supply. The output terminal 264 is electrically connected to the solenoid 225, the solenoid being returned to the other side of the power supply. Output terminal 264 is also electrically connected to a solenoid-actuated pneumatic control valve 267. Control valve 267 has two operating solenoids, one for each of two different operating conditions. The second solenoid in valve 267 is electrically connected to the second output terminal 265 of control switch 261. Control valve 267 is provided with appropriate pneumatic connections to the opposite ends of cylinder 231. The control valve also has an input connection from a suitable supply of air under pressure, and an exhaust port.

In considering the operation of interleaver 200, the starting point may be taken as the operational condition illustrated in FIG. 10. In the position shown, the transfer means comprising carriage 251 has gripped a paper sheet 271 and has initiated movement in the direction of the arrow B toward an interleaving position at which the paper sheet will be released as it is engaged by a hamburger patty or like article. The control switch 261 is in the position shown in FIGS. and 11 and completes an electrical circuit to one of the solenoids of control valve 267, actuating the control valve to supply air under pressure to the top of cylinder 231 and to exhaust the bottom of the cylinder. Accordingly, the piston shaft 233 and rack 234 are driven downwardly, rotating the input gear 237 of the unidirectional clutch 238 in a counterclockwise direction. For counterclockwise rotation, clutch 238 completes a drive connection to its output gear 242, rotating gear 242 counterclockwise and hence driving gear 243 clockwise. The rotation of gear 243 causes a corresponding rotation of the paper feed roller 244 so that the paper web 222 is advanced through the interleaver onto guide 216. The length of the paper fed into the interleaver guide is determined by the stroke of rack 234.

When carriage 251 returns, in the direction of the arrow A, it ultimately reaches the position illustrated in FIG. 9 with the vacuum pads 254 and 255 positioned adjacent the front end of guide 216. At this time, the rotational movement of cam shaft 215, which is synchronized with the hamburger patty machine or other processing machine for the articles with which the paper is interleaved, brings the reduced diameter portions of cams 213 and 214 into alignment with the cam follower projections 211 and 212. As a consequence, the main body ofinterleaver 200 pivots a short distance in a counterclockwise direction, moving the left-hand portion of the interleaver downwardly so that the portion of the paper web 222 that has been extended into the interleaver contacts vacuum pads 254 and 255. This also actuates switch 261 to its alternate operating condition, connecting the power line to output terminal 264 instead of terminal 265.

The change in control switch 261 de-energizes the one solenoid in control valve 267 and energizes the other control valve solenoid. As a consequence, air under pressure is supplied to the lower end of cylinder 231 and the upper end of the cylinder is connected to the exhaust port. The piston shaft 233 and rack 234, as a consequence, are driven upwardly back to the position shown in FIG. 10. This does not cause reverse rotation of the paper feed rolls 244 and 245 because the unidirectional clutch 238 does not complete a drive connection to its output gear 242 for the resulting clockwise rotation of its input gear 237. Thus, the change in connections for control valve 267 merely returns the cylinder 231 and the rack 234 to their original operating condition ready for the next feed cycle of the paper web 222.

The change in operating conditions for the control switch 261 also energizes solenoid 225. As a consequence, the solenoid drives knife blade 224 downwardly, severing the portion of the paper web 222 that has been extended into the guide 216 and thus effectively depositing a single sheet of paper on the guide 216.

With continued rotation of cam shaft 213, the full diameter portions of the cams 213 and 214 again engage the cam followers 211 and 212, pivoting the interleaver back to the position shown in FIG. 10. The vacuum gripper 254 and 255 maintain their grip on the lead comers of the paper sheet that has been deposited on the support means comprising the bottom plate 217 of guide 216. As a consequence, the paper sheet is bent or creased in its central portion, due to the presence of the V-shaped element 218. Consequently, the subsequent movement of carriage 251 away from the main portion of the interleaver creases the paper longitudinally so that is it selfsupported as a cantilever element on the vacuum pads 254 and 255. The return of the interleaver to its original position also actuates control switch 261 back to its initial operating condition. The knife blade 224 is retracted by springs 227 and a further paper feed cycle is initiated in preparation for the subsequent return movement of carriage 251 as described above.

it is thus seen that the basic operation of interleaver 200 is essentially similar to that of interleavers 20 and 120. The principal difference is that the individual sheets of paper are cut from the continuous web 222 instead of being pre-cut and stored in a supply hopper. The interleaver is still maintained in synchronism with the associated equipment producing the articles with which the paper is interleaved, through appropriate drive connections of the kind described more fully in the previous embodiments.

In the embodiments of the invention described above, the paper supply is nonnally maintained at a slightly elevated location relative to the transfer position of the carriage. Transfer is initiated by lowering the paper to engage the grippers on the carriage at the transfer position, then raising the paper supply means to begin the transfer cycle. The same effect can be achieved by a limited movement of the carriage, transverse to the transfer path, using a stationary paper supply, but this tends toward undue complication of the control and construction of the carriage. Mechanical synchronizing and drive connections to the apparatus producing the articles to be interleaved with the paper have been shown, but electrical, pneumatic or hydraulic controls can be employed if desired.

lclaim:

1. A sheet interleaver device for interleaving individual thin, flexible sheets of paper, cellophane, plastic film or like material with a series of relatively thick, flat articles as the articles traverse a given stacking path, one by one in spaced relation to each other, said stacking path terminating at a stacking position, said interleaver device comprising:

support means for supporting a thin, flexible sheet of given length and width at a transfer position adjacent to but spaced from an intermediate interleaving position on said stacking path;

supply means for sequentially positioning a series of thin,

flexible sheets of said given length and width on said support means; transfer means for transferring a flexible sheet from said support means, along a predetermined transfer path originating at said transfer position and terminating at said interleaving position on said stacking path, and for supporting said sheet cantilever-fashion at said interleaving position; and shaping means, interposed in said transfer path, for bending each sheet to impart sufficient stiffness to the sheet to render it self-supporting as a cantilever member;

said transfer means operating in synchronism with the movement of said articles along said stacking path so that each article engages a cantilever sheet at said interleaving podtion and carries that sheet with the article to the stacking position.

2. A sheet interleaver device, according to claim 1, in which said supply means comprises a hopper for retaining a stack of pre-cut sheets at said transfer location, and in which said support means comprises the bottom of said hopper, said hopper having a bottom opening to permit feeding sheets one-by-one from the bottom of the hopper, and said shaping means comprising a substantially V-shaped shaper member projecting into the bottom opening of the hopper.

3. A sheet interleaver device, according to claim 2, in which said shaper member is mounted in the bottom of said hopper and compriSes an integral part of said support means.

4. A sheet interleaver device, according to claim 3, in which said bottom opening in said hopper extends across the entire front side of the hopper, facing said transfer means, and in which said support means includes a pair of small comer supports at the front corners of said opening.

5. A sheet interleaver device, according to claim 1, in which said transfer means comprises a carriage movable between said transfer position and said interleaving position, a pair of grippers mounted on said carriage in alignment with an opening in said support means when said carriage is at said transfer position, and means for effecting limited relative movement between said carriage and said support means, at said transfer position, to engage said grippers with adjacent comers of a sheet on said support means and to enable said carriage to pull said sheet from said support means across said shaping means.

6. A sheet interleaver device, according to claim 5, in which said support means is mounted for limited pivotal movement in a vertical direction, and including actuating means comprising a cam and a cam follower for pivoting said support means over a limited arc, and means for moving said cam in synchronism with movements of said carriage.

7. A sheet interleaver device, according to claim 1, in which said supply means comprises a continuous web of thin, flexible material of said given width, web feed means for feeding the web across said support means, and means for severing a sheet of said predetermined length from said web as said web is fed onto said support means.

8. A sheet interleaver device, according to claim 7, in which said shaper means comprises a V-shaped shaper member mounted on said support means as a part thereof and projecting into a bottom opening in said support means.

9. A sheet interleaver device, according to claim 8, in which said bottom opening in said support meanS extends across the front side thereof, facing said transfer means.

10. A sheet interleaver device according to claim 1, in which said transfer means comprises a pair of spaced grippers for gripping a sheet on said support means near the comers of one leading edge of the sheet, and release means for actuating said grippers to release the sheet at said interleaving position in approximate synchronism with engagement of the sheet by an article traversing said stacking path.

ll. A sheet interleaver device according to claim 10, in which each gripper comprises a vacuum pad connected to a vacuum pump, and said release means comprises a valve, actuated in synchronism with said transfer means, for closing the connection to said vacuum pump as each article arrives at said interleaving position.

12. A sheet interleaver device according to claim 11, in which said vacuum pads are connected to a vacuum manifold comprising a part of a carriage of generally U-shaped configuration with the bight portion thereof extending transversely of said transfer path and into engagement with a pair of guide rails that extend parallel to opposite sides of said transfer path, said guide rails guiding said carriage for movement along said transfer path, the spacing between said guide rails being substantially greater than the width of said sheets.

13. A sheet interleaver device for interleaving individual thin, flexible sheets of paper, cellophane, plastic film or like material with a series of relatively thick, flat articles as the articles traverse a given stacking path, one by one in spaced relation to each other, said stacking path terminating at a stacking position, said interleaver device comprising:

supply means, including a bottom support member having a feed opening therein, for supporting a stack of pre-cut,

thin, flexible sheets of given length and width at a transfer position adjacent to but spaced from an intermediate position on said stacking path;

transfer means for transferring a single bottommost flexible sheet from said support means, along a predetermined transfer path originating at said transfer position and terminating at said interleaving position on said stacking path, and for supporting said sheet at said interleaving position, the initial portion of said transfer path extending substantially normal to the plane of said single sheet,

said transfer means comprising a pair of vacuum grippers engaging opposite edges of said single sheet and means for releasing said vacuum grippers when said single sheet is at said interleaving position,

said transfer means operating in synchronism with the movement of said articles along said stacking path so that each article engages a single sheet at said interleaving position, upon release of said vacuum grippers, and carries that sheet with the article to the stacking position.

14. A sheet interleaver device, according to claim 13, in which said feed opening in said bottom support member extends across the entire front of the support member, facing said transfer means, and in which said support member includes a pair of small corner supports at the front corners of said opening.

15. A sheet interleaver device, according to claim 13, in which said transfer means comprises a carriage movable between said transfer position and said interleaving position, in which said vacuum grippers are mounted on said carriage in alignment with said feed opening in said bottom support member when said carriage is at said transfer position, and means for effecting limited relative movement between said carriage and said support member, at said transfer position, to engage said grippers with adjacent corners of said bottommost sheet on said support member and to enable said carriage to pull said sheet from said support in a direction normal to the plane of said single sheet.

l6. A sheet interleaver device for interleaving individual thin, flexible sheets of paper, cellophane, plastic film or like material with a series of relatively thick, flat articles as the articles traverse a given stacking path, one by one in spaced relation to each other, said stacking path terminating at a stacking position, said interleaver device comprising:

support means for supporting a thin, flexible sheet of given length and width at a transfer position adjacent to but spaced from an intermediate interleaving position on said stacking path;

supply means for sequentially positioning a series of thin,

flexible sheets of said given length and width on said support means;

transfer means for transferring a flexible sheet from said support means, along a predetermined transfer path originating at said transfer position and terminating at said interleaving position on said stacking path, said transfer means comprising a carriage reciprocally movable along said path, a pair of spaced vacuum grippers for gripping the opposite sides of a sheet on said support means, and release means for actuating said grippers to release the sheet at said interleaving position in approximate synchronism with engagement of the sheet by an article traversing said stacking path;

said transfer means operating in synchronism with the movement of said articles along said stacking path so that each article engages a single sheet at said interleaving position, upon release of said vacuum grippers, and carries that sheet with the article to the stacking position.

17. A sheet interleaver device according to claim I, in which each gripper comprises a vacuum pad connected to a vacuum pump, and said release means comprises a valve, actuated in synchronism with said transfer means, for closing the connection to said vacuum pump as each article arrives at said interleaving position, in which said vacuum pads are connected to a vacuum manifold comprising a part of said car- 

1. A sheet interleaver device for interleaving individual thin, flexible sheets of paper, cellophane, plastic film or like material with a series of relatively thick, flat articles as the articles traverse a given stacking path, one by one in spaced relation to each other, said stacking path terminating at a stacking position, said interleaver device comprising: support means for supporting a thin, flexible sheet of given length and width at a transfer position adjacent to but spaced from an intermediate interleaving position on said stacking path; supply means for sequentially positioning a series of thin, flexible sheets of said given length and width on said support means; transfer means for transferring a flexible sheet from said support means, along a predetermined transfer path originating at said transfer position and terminating at said interleaving position on said stacking path, and for supporting said sheet cantilever-fashion at said interleaving position; and shaping means, interposed in said transfer path, for bending each sheet to impart sufficient stiffness to the sheet to render it self-supportIng as a cantilever member; said transfer means operating in synchronism with the movement of said articles along said stacking path so that each article engages a cantilever sheet at said interleaving position and carries that sheet with the article to the stacking position.
 2. A sheet interleaver device, according to claim 1, in which said supply means comprises a hopper for retaining a stack of pre-cut sheets at said transfer location, and in which said support means comprises the bottom of said hopper, said hopper having a bottom opening to permit feeding sheets one-by-one from the bottom of the hopper, and said shaping means comprising a substantially V-shaped shaper member projecting into the bottom opening of the hopper.
 3. A sheet interleaver device, according to claim 2, in which said shaper member is mounted in the bottom of said hopper and comprises an integral part of said support means.
 4. A sheet interleaver device, according to claim 3, in which said bottom opening in said hopper extends across the entire front side of the hopper, facing said transfer means, and in which said support means includes a pair of small corner supports at the front corners of said opening.
 5. A sheet interleaver device, according to claim 1, in which said transfer means comprises a carriage movable between said transfer position and said interleaving position, a pair of grippers mounted on said carriage in alignment with an opening in said support means when said carriage is at said transfer position, and means for effecting limited relative movement between said carriage and said support means, at said transfer position, to engage said grippers with adjacent corners of a sheet on said support means and to enable said carriage to pull said sheet from said support means across said shaping means.
 6. A sheet interleaver device, according to claim 5, in which said support means is mounted for limited pivotal movement in a vertical direction, and including actuating means comprising a cam and a cam follower for pivoting said support means over a limited arc, and means for moving said cam in synchronism with movements of said carriage.
 7. A sheet interleaver device, according to claim 1, in which said supply means comprises a continuous web of thin, flexible material of said given width, web feed means for feeding the web across said support means, and means for severing a sheet of said predetermined length from said web as said web is fed onto said support means.
 8. A sheet interleaver device, according to claim 7, in which said shaper means comprises a V-shaped shaper member mounted on said support means as a part thereof and projecting into a bottom opening in said support means.
 9. A sheet interleaver device, according to claim 8, in which said bottom opening in said support means extends across the front side thereof, facing said transfer means.
 10. A sheet interleaver device according to claim 1, in which said transfer means comprises a pair of spaced grippers for gripping a sheet on said support means near the corners of one leading edge of the sheet, and release means for actuating said grippers to release the sheet at said interleaving position in approximate synchronism with engagement of the sheet by an article traversing said stacking path.
 11. A sheet interleaver device according to claim 10, in which each gripper comprises a vacuum pad connected to a vacuum pump, and said release means comprises a valve, actuated in synchronism with said transfer means, for closing the connection to said vacuum pump as each article arrives at said interleaving position.
 12. A sheet interleaver device according to claim 11, in which said vacuum pads are connected to a vacuum manifold comprising a part of a carriage of generally U-shaped configuration with the bight portion thereof extending transversely of said transfer path and into engagement with a pair of guide rails that extend parallel to opposite sides of said transfer path, said guide rails guiding said carriage for movement along said transfer path, the spacing between said guide rails being substantially greater than the width of said sheets.
 13. A sheet interleaver device for interleaving individual thin, flexible sheets of paper, cellophane, plastic film or like material with a series of relatively thick, flat articles as the articles traverse a given stacking path, one by one in spaced relation to each other, said stacking path terminating at a stacking position, said interleaver device comprising: supply means, including a bottom support member having a feed opening therein, for supporting a stack of pre-cut, thin, flexible sheets of given length and width at a transfer position adjacent to but spaced from an intermediate position on said stacking path; transfer means for transferring a single bottommost flexible sheet from said support means, along a predetermined transfer path originating at said transfer position and terminating at said interleaving position on said stacking path, and for supporting said sheet at said interleaving position, the initial portion of said transfer path extending substantially normal to the plane of said single sheet, said transfer means comprising a pair of vacuum grippers engaging opposite edges of said single sheet and means for releasing said vacuum grippers when said single sheet is at said interleaving position, said transfer means operating in synchronism with the movement of said articles along said stacking path so that each article engages a single sheet at said interleaving position, upon release of said vacuum grippers, and carries that sheet with the article to the stacking position.
 14. A sheet interleaver device, according to claim 13, in which said feed opening in said bottom support member extends across the entire front of the support member, facing said transfer means, and in which said support member includes a pair of small corner supports at the front corners of said opening.
 15. A sheet interleaver device, according to claim 13, in which said transfer means comprises a carriage movable between said transfer position and said interleaving position, in which said vacuum grippers are mounted on said carriage in alignment with said feed opening in said bottom support member when said carriage is at said transfer position, and means for effecting limited relative movement between said carriage and said support member, at said transfer position, to engage said grippers with adjacent corners of said bottommost sheet on said support member and to enable said carriage to pull said sheet from said support in a direction normal to the plane of said single sheet.
 16. A sheet interleaver device for interleaving individual thin, flexible sheets of paper, cellophane, plastic film or like material with a series of relatively thick, flat articles as the articles traverse a given stacking path, one by one in spaced relation to each other, said stacking path terminating at a stacking position, said interleaver device comprising: support means for supporting a thin, flexible sheet of given length and width at a transfer position adjacent to but spaced from an intermediate interleaving position on said stacking path; supply means for sequentially positioning a series of thin, flexible sheets of said given length and width on said support means; transfer means for transferring a flexible sheet from said support means, along a predetermined transfer path originating at said transfer position and terminating at said interleaving position on said stacking path, said transfer means comprising a carriage reciprocally movable along said path, a pair of spaced vacuum grippers for gripping the opposite sides of a sheet on said support means, and release means for actuating said grippers to release the sheet at said interleaving position in approximate synchronism with engagement of the sheet by an article traversing said stacking path; said transfer means operating in synchronisM with the movement of said articles along said stacking path so that each article engages a single sheet at said interleaving position, upon release of said vacuum grippers, and carries that sheet with the article to the stacking position.
 17. A sheet interleaver device according to claim 1, in which each gripper comprises a vacuum pad connected to a vacuum pump, and said release means comprises a valve, actuated in synchronism with said transfer means, for closing the connection to said vacuum pump as each article arrives at said interleaving position, in which said vacuum pads are connected to a vacuum manifold comprising a part of said carriage, and in which said carriage is of generally U-shaped configuration with the bight portion thereof extending transversely of said transfer path and into engagement with a pair of guide rails that extend parallel to opposite sides of said transfer path, said guide rails guiding said carriage for movement along said transfer path, the spacing between said guide rails being substantially greater than the width of said sheets. 